Continuous-extraction mining system

ABSTRACT

A material extraction system for an underground mine includes an elevated haulage conveyor extending between first and second ends of a roadway entry. The haulage conveyor is cantilevered from a mine wall and conveys material toward either end of the roadway entry. The system also includes a crusher including a drive operable to move the crusher along the roadway entry. The system further includes a bridge conveyor including a first end adjacent the crusher and receiving material from the crusher, and a second end adjacent the elevated haulage conveyor and positioned for depositing material onto the elevated haulage conveyor. The bridge conveyor is moveable with the crusher along the roadway entry. The system also includes a loader moveable along the roadway entry and into and out of material collection entries to collect material therefrom and transport the material to the crusher.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of and priority to U.S. patentapplication Ser. No. 13/179,266, filed Jul. 8, 2011, and U.S.Provisional Patent Application Nos. 61/362,949, filed Jul. 9, 2010 and61/435,121, filed Jan. 21, 2011. The entire contents of each of theforegoing applications are incorporated by reference herein.

BACKGROUND

In underground hard-rock mining, a process called block caving can beused. In this process, an ore body is typically preconditioned byfracturing the ore via various methods. Conical or tapered voids arethen drilled at the bottom of the ore body, and the void is blasted. Thefractured ore body above the blast will cave, and, through gravity, fallor settle down into collection areas called draw-bells. The draw-bellsserve as discharge points to an entryway. Load-haul-dump vehiclestypically tram through the entryway to load ore from the draw-bell. Thevehicles haul the ore through various other entryways to acentrally-located dump point and dump the ore into an undergroundcrusher that has been installed at the dump point. The crushed oresubsequently is fed to a conveyor system to be conveyed out of the mine.As more ore is removed from the draw-bells, the ore body caves infurther, providing a continuous stream of ore.

SUMMARY

In some embodiments, a conveyor system for an underground mine extendsthrough an underground entry having a floor, a wall, and a roof. Theconveyor system generally includes a bridge conveyor extending generallyupwardly toward the roof from a location proximal to the floor, and ahaulage conveyor cantilevered from the wall and positioned proximal tothe roof. The bridge conveyor conveys material upwardly and deposits thematerial onto the haulage conveyor.

In other embodiments, a material extraction system is provided for anunderground mine, the mine including a roadway entry having a first endand a second end, the mine also including a first material collectionentry that intersects the roadway entry between the first and secondends, and a second material collection entry that intersects the roadwayentry between the first and second ends and spaced along the roadwayentry from the first material collection entry. The system generallyincludes an elevated haulage conveyor extending along the roadway entrybetween the first and second ends. The haulage conveyor is operable toconvey material toward at least one of the first and second ends. Thesystem also includes a material collector positioned between the firstand second ends and operable to move along the roadway entry. The systemfurther includes a bridge conveyor including a first end adjacent thematerial collector and receiving material from the material collector,and a second end adjacent the elevated haulage conveyor and positionedfor depositing material onto the elevated haulage conveyor. The bridgeconveyor is moveable with the material collector along the roadwayentry. The system also includes a loader moveable along the roadwayentry and into and out of the first and second material collectionentries to collect material therefrom and to deposit material into thematerial collector.

In still other embodiments, a load haul dump vehicle is provided formoving material through an underground mine. The vehicle generallyincludes a front end including a moveable load bucket, a rear endpivotally coupled to the front end, and an electrical drive operable tomove the load bucket and the vehicle.

In other embodiments, a material extraction system is provided for anunderground mine. The mine includes a roadway entry and a draw-bellentry intersecting the roadway entry and affording access to adraw-bell. The system generally includes a conveyor extending along theroadway entry, roadway rails extending along the roadway entry, and amaterial collector moveable along the roadway rails. The materialcollector is operable to deposit material onto the conveyor. The systemalso includes a loader that is moveable from the roadway entry into thedraw-bell entry for removing material from the draw-bell andtransferring material removed from the draw bell to the materialcollector.

In still other embodiments, a loader is provided for underground mining.The loader generally includes a chassis having a front end and a rearend, a conveyor extending between the front end and the rear end, and aloading arm coupled to the chassis and positioned over the front end.The loading arm is operable to reach beyond the front end of the chassisfor maneuvering material onto the conveyor.

Other aspects of the invention will become apparent by consideration ofthe detailed description and accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic diagram of a block caving mining setup depictingan ore body, draw-bells, and undercut entryway.

FIG. 2 is a top view of a first type of block-caving infrastructure witha chevron-type draw-bell layout, showing a first continuous-extractionsystem.

FIG. 3 is a top perspective view of the first continuous-extractionsystem shown in FIG. 2.

FIG. 4 is an elevational view of the first continuous-extraction systemshown in FIG. 2.

FIG. 5 is a bottom perspective view of a loader suitable for use withthe first continuous-extraction system of FIG. 3.

FIG. 6 is a top perspective view of an alternative embodiment of theloader of FIG. 5.

FIG. 7 is a perspective view of an alternative embodiment of the loaderof FIGS. 5 and 6.

FIG. 8 is a rear perspective view of the continuous-extraction system ofFIG. 3, showing a cable-handling system for powering thecontinuous-extraction system.

FIG. 9 is a perspective view of a second continuous-extraction systemincluding a feeder, a material collector, and a bridge conveyor thatfeed material to an elevated and cantilevered haulage conveyor.

FIG. 10 is an end view of the continuous-extraction system of FIG. 9.

FIG. 11 is a top view of the continuous-extraction system of FIG. 9.

FIG. 12 is a top view of an alternative continuous-extraction system.

It should be understood that the invention is not limited in itsapplication to the details of construction and the arrangements of thecomponents set forth in the following description or illustrated in theabove-described drawings. The invention is capable of other embodimentsand of being practiced or being carried out in various ways. Also, it isto be understood that the phraseology and terminology used herein is forthe purpose of description and should not be regarded as limiting.

DETAILED DESCRIPTION

FIG. 1 illustrates a block-caving mining process, where fractured orebody 2, such as copper or gold ore, caves and falls by gravity toward aseries of draw-bells 4. The draw-bells 4 are discharge points to roadwayentries 6 that extend below the fractured ore body 2 and lead to otherunderground entries that permit material extracted from the draw-bells 4to be transported to the surface. With reference also to FIG. 2, ablock-caving infrastructure 8 typically includes a plurality ofdraw-bells 4 (e.g., sixteen, as shown) distributed through a miningblock. The block-caving infrastructure 8 can be several hundred orseveral thousand meters underground. In the illustrated infrastructure8, each draw-bell 4 is connected to adjacent roadway entries 6 by a pairof angled draw-bell entries 9. The draw-bell entries 9 leading to eachdraw bell 4 are oriented at an obtuse angle relative to the adjacentroadway entry 6 to form a chevron pattern, as can be seen in FIG. 2.This chevron pattern simplifies movement of mining equipment between theroadway entries 6 and the draw-bell entries 9, as discussed furtherbelow. Each roadway entry 6 leads to a transverse transport entry 11,which in turn leads to other entries that allow material removed fromthe draw-bells 4 to be transported to the surface.

Referring also to FIGS. 3-4, a continuous-extraction system 10 ismoveable along the roadway entries 6 and into the draw-bell entries 9for removing fractured ore 2 from the draw-bell 4. Thecontinuous-extraction system 10 is an interconnected set of railcars andincludes a primary drive and power center 12, a material collector inthe form of a crusher or sizer 14, a bridge conveyor 16, and a loader orloading machine 18. The loading machine 18 is positioned at the frontend 20 of the continuous-extraction system 10. The continuous-extractionsystem 10 can traverse fore and aft on track rails 22 that run throughthe block-cave infrastructure 8. As best shown in FIG. 4, the trackrails 22 include an integrated conveyor system 24 positioned below therails 22. The continuous-extraction system 10 thus runs on track rails22, below which the conveyor system 24 runs in a substantially parallelmanner. The conveyor system 24 can be a belt or chain-type conveyor. Byway of example only, the figures depict a belt-type troughing conveyor.

As shown in FIG. 2, sets of track rails 22 extend along each of theroadway entries 6 and provide access to the draw-bells 4. At eachdraw-bell entry 6, a rail spur 23 diverges away from the track rails 22and extends into the draw-bell entry 9. To access each draw-bell 4 froma given track rail 22, the continuous-extraction system 10 can makealternating left and right turns at obtuse angles into the draw-bellentries 9. In this regard, the continuous-extraction system 10 includestrack switches (not shown) that allow the continuous-extraction system10 to turn onto the rail spur 23 and advance into the draw bell-entry 9.The track switch can be mounted anywhere on the track rails 22.

In some embodiments, including those illustrated in FIGS. 3 and 4, theloading machine 18 advances into the draw-bell entry 9 while the powercenter 12 and crusher 14 remain on the track rails 22. General operationof the continuous-extraction system 10 is as follows—the loading machine18 gathers material from the draw-bell 4 and deposits it onto the bridgeconveyor 16, which extends rearwardly from the loading machine 18. Thebridge conveyor 16 extends from the draw-bell entry 9 into the roadwayentry 6 and transports ore 2 gathered from the draw-bell 4 by theloading machine 18 to the crusher 14.

The crusher 14 crushes the ore 2 to an acceptable size and dischargesthe crushed ore 2 onto the conveyor 24 that runs below the track rails22. The conveyor 24 conveys the crushed ore to the transverse transportentry 11 (see FIG. 2) and out of the mine. The ore 2 thus continuouslymoves from the loading machine 18, to the bridge conveyor 16, to thecrusher 14, to the conveyor 24, and then outside the mine.

Depending on the material being mined and the type of materialpreconditioning that is performed, some mining environments may notrequire the use of the crusher 14. In such instances, the crusher 14 canbe replaced by a simplified material collector for receiving materialfrom the loading machine 18 and depositing the material onto theconveyor 24 without further crushing or sizing of the material. Such amaterial collector may include intermediate conveyors or other poweredmaterial transport devices, or may be or include one or more funnels orchutes for guiding material received from the loading machine 18 ontothe conveyor 24. Like the illustrated crusher 14, the material collectorcan be separate from the primary drive and power center 12 or, in someembodiments, the crusher 14 or the material collector can be integralwith the primary drive and power center 12.

The continuous-extraction system 10 includes one or more drivemechanisms for tramming along the track rails 22 and the rail spurs 23.After completing an operation at a given draw-bell 4, thecontinuous-extraction system 10 can tram backwards until the loadingmachine 18 is once again positioned on the track rails 22. Thecontinuous-extraction system 10 then advances to the next draw-bell 4 torepeat the ore-loading process. One or both of the primary drive andpower center 12 and crusher 14 (if required) can include a suitabledrive mechanism for moving the continuous-extraction system 10 along thetrack rails 22 and for pushing and pulling the loading machine 18 intoand out of the rail spurs 23. In a block-cave infrastructure 8 withmultiple draw-bells 4, a plurality of continuous-extraction systems 10can be employed to improve production rates.

Referring also to FIGS. 5 and 6, the loading machine 18 includes achassis 38 that rides along the track rails 22 and the rail spur 23. Thechassis 38 is substantially wedge-shaped and includes a conveyor 26extending from a front end to a rear end of the chassis 38. The frontend of the chassis 38 also includes a collection tray 27 optionallyincluding a pair of rotating collector wheels 28 that guide materialonto the conveyor 26. The conveyor 26 receives the material removed fromthe draw bell 4, transports it rearwardly and upwardly, and deposits itonto the bridge conveyor 16.

The loading machine 18 also includes a carriage assembly 31 that ismoveable in the fore and aft direction along the chassis 38 and hasmounted thereto a backhoe-type loading arm 30. The loading arm 30 isoperable to reach beyond the front end of the chassis into the draw-bell4 and to move (e.g., to pull) material onto the collection tray 27. Theillustrated loading arm 30 also includes a rock breaker 32 operable tobreak down large lumps of ore 2 that would be too large for the loadingarm 30 to collect and maneuver onto the collection tray 27. In theillustrated embodiment, the rock breaker 32 is in the form of a jackhammer, but other embodiments may include other types of rock breakerssuch as drills, shearing type devices, and the like.

In operation, ore 2 is pulled from the draw-bell 4 by the backhoe-typeloading arm 30, onto the collection tray 27 where the optional rotatingcollector wheels 28 help guide the material onto the conveyor 26. Theconveyor 26 then conveys the material rearwardly and upwardly anddeposits it onto the bridge conveyor 16. In the illustrated embodiments,both the conveyor 26 and the bridge conveyor 16 employ a plate-typeconveyor.

As shown in FIG. 7, some embodiments of the invention may include analternative type of loading machine 18 that is able to move off of andonto a flatbed or “lowboy” rail car 15 positioned on the track rails 22.In such embodiments, instead of rail-car-type wheels for movement overrails, the loading machine 18 includes treads or wheels 17, 19 (wheelsare shown in FIG. 7) for movement over the mine floor. As such, the railspurs 23 that extend into the draw-bell entries 9 can be eliminated. Thealternative loading machine 18 includes sets of transfer members in theform of the wheels 17, 19 that are operable to move the front end 20 ofthe loading machine 18 toward the draw-bell entry 9. The transfer wheels17, 19 are rotatable about a generally vertical axis 21 for movement ina variety of directions. The transfer wheels 17, 19 also are verticallymoveable relative to the chassis 38 of the loading machine 18 and areable to “step off” of the lowboy rail car 15 and engage the mine floor65. For example, the transfer wheels 17, 19 move the loading machine 18sideways until the first transfer wheel 17 is off the lowboy rail car 15while the other transfer wheel 19 remains on the lowboy rail car 15. Thefirst transfer wheel 17 is then moved downwardly until it engages themine floor 65, and both transfer wheels 17, 19 then operate to move theloading machine 18 generally laterally until the second transfer wheel19 is positioned off of the lowboy rail car 15 and can be lowered ontothe mine floor 65. Once all of the transfer wheels 17, 19 are positionedon the mine floor 65, the transfer wheels 17, 19 lower the chassis 38toward the mine floor 65 and then rotate about the axes 21 for movementin a generally forward direction into the draw-bell entry 9. Inalternative embodiments the loading machine 18 may include a separateset of fixed wheels configured for forward movement into the draw-bellentry 9. In such embodiments, the transfer wheels 17, 19 can be movedvertically upwardly a sufficient amount to remain out of the way whilethe fixed wheels maneuver the loading machine 18 to collect materialfrom the draw-bell 4. The operation is performed in reverse to returnthe loading machine 18 to the lowboy rail car 15.

Referring back to FIG. 5, a first crowding mechanism 39 that helps theloading machine 18 gather material from the draw-bell 4 is illustrated.The crowding mechanism 39 is an optional feature that can help urge theloading machine 18 and the rest of the continuous-extraction system 10closer to the draw-bell 4, thereby making it easier for the loading arm30 to maneuver ore 2 onto the collection tray 27 and enhancing theloading operation. The crowding mechanism 39 of FIG. 5 includes atelescoping hydraulic cylinder 34 coupled to the chassis 38 of theloading machine 18 and a movable portion in the form of a hook 36positioned on an end of the hydraulic cylinder 34. The hook 36 isconfigured to engage a fixed member in the form of a bar 40 that isfixed relative to the mine floor 65 at a location within the draw-bellentry 9. In other constructions, the bar 40 could instead be positionedin the roadway entry 6. In the illustrated embodiment, the bar 40 iscoupled to a portion of the rail spur 23. In other embodiments, the bar40 is anchored to the mine floor 65. In operation, the hook 36 engagesthe bar 40 and the hydraulic cylinder 34 is actuated to pull or push(depending on the specific configuration and location of the hook 36relative to the loading machine 18) the loading machine 18 toward thedraw-bell 4. As the loading machine 18 moves toward the draw-bell 4,some ore 2 may be pushed onto the collection tray 27 without requiringuse of the loading arm 30. Once the loading machine 18 has been advancedas far into the draw-bell 4 as possible, the loading arm 30 can then beused to maneuver additional ore 2 onto the collection tray 27.

FIG. 6 illustrates a second crowding mechanism 41 that can be analternative or a supplement to the first crowding mechanism 39 of FIG.5. The second crowding mechanism 41 includes a movable portion in theform of a pinion 42 coupled to the loading machine 18 and a fixedportion in the form of a rack 44 that is fixed relative to the minefloor 65 and that is engaged by the pinion 42. The rack 44 can beanchored directly to the mine floor 65 or can be mounted on a portion ofthe rail spur 23. The pinion 42 is coupled to a drive mechanism 45 thatis operable to drive the pinion 42. In some embodiments, the pinion 42is driven by the same drive mechanism that drives the wheels of theloading machine 18. When the pinion 42 is driven while engaged with therack 44, the pinion 42 urges the loading machine 18 toward the draw-bell4. While FIG. 6 shows the pinion 42 coupled to a rear wheel of theloading machine 18, in other embodiments the pinion 42 can be separatefrom the wheels or coupled to more and/or other wheels of the loadingmachine 18, such as the front wheels, rear wheels, or combinationsthereof.

Referring to FIG. 8, in some embodiments, the continuous-extractionsystem 10 is powered by overhead cables that are enclosed within aBretby-type cable handling system 46. The Bretby-type cable handlingsystem 46 is a flexible carrier consisting of a series of flat plates.The plates are paired, one forming a bottom and the other a top, and thesides are connected by pins. The top and bottom plates and the side pinsencase an area where cables can be handled. Each pair of plates is thenconnected to an adjacent pair of plates, forming a chain that resemblescontinuous tracks on heavy equipment. Power cables 47 can drop down froman overhead cable trough 48 to the power center 12. The power center 12is typically the last car of the continuous-extraction system 10 andpowers elements of the continuous-extraction system 10, such as thecrusher 14, conveyor 16, loading machine 18, and various controlsassociated therewith. In other embodiments, a monorail overhead withtrolleys can be used in place of the Bretby-type cable handling system46.

In other embodiments, the continuous-extraction system 10 is powered byelectrical plug-in stations at each draw-bell 4. Thecontinuous-extraction system 10 can be equipped with cable reels thatreel in and pay out cables that connect to nearby plug-in stations alongthe roadway entry 6 and supply power to the system 10. In operation, anonboard operator initially plugs in the electrical cable to a proximalplug-in station, thus powering the system 10 through a cable from theproximal plug-in station. As the system 10 moves from a proximal plug-instation to a distal plug-in station, the onboard operator can pluganother electrical cable to the distal plug-in station. The operator orsystem then reconfigures the internal power management system so thatthe system 10 is powered through cables from the distal plug-in station.After the internal power management has been reconfigured, the operatorcan unplug the cable to the proximal plug-in station. This way, eachcable does not run the entire length between plug-in stations, andtherefore in some embodiments the length of cable needed on the reelscan be minimized. The plug-in stations can be disposed on the floor orwall of the mine at each draw-bell 4 or mounted on a supportingstructure.

In still other embodiments, the continuous-extraction system 10 includesa self-contained power supply for moving from one draw-bell 4 to anotherafter being disconnected from an external source of power, such as theBretby-type cable handling system 46 discussed above. In someembodiments, the continuous-extraction system 10 is powered throughbatteries, a small diesel power unit, or a hybrid unit. The system 10can be powered for example through multiple batteries, where one or morebatteries are being charged while the others are being used. In someembodiments, the system 10 can be powered by a hybrid of diesel engineand batteries, where a diesel engine runs to charge the battery, forexample between high load demands, between shifts, at break times, andthe like. The batteries, small diesel power unit, or hybrid unit can beused to drive electric and/or electro-hydraulic motors and drivesystems. Because it remains substantially stationary, the conveyorsystem 24 that runs through the block-cave infrastructure 8 can bepowered from stationary power centers that are independent from theoverhead power cables or other power sources associated with thecontinuous-extraction system 10.

Some embodiments can also include automation equipment operable toposition the continuous-extraction system 10 at draw-bells 4 and tocontrol other movements as needed. For example, remote cameras can beemployed to help operate the backhoe-type loading arm 30 and maneuverand operate the continuous-extraction system 10 into the draw-bell 4from a remote location. Radio or cable communication links can be usedto a similar extent, with or without the remote operation cameras. Insome embodiments, an operator for the remote operation cameras,communication links, or both, can be located underground. In otherembodiments, the operator can be located above ground. An above groundoperator can be many kilometers away from the mine. In yet otherembodiments, the continuous-extraction system 10 can containposition-sensing devices for automation, remote operation, or both.

FIGS. 9 and 10 illustrate an alternative form of a continuous-extractionsystem 50. The continuous-extraction system 50 includes a loader in theform of a load-haul-dump machine (“LHD”) 52, a feeder 54, a combinedpower center and material collector in the form of a mobile crusher 56,a bridge conveyor 58, and an elevated and cantilevered haulage conveyor60. Unlike the continuous-extraction system 10 described above, whichincludes tracks 22 and a conveyor 24 that occupy the mine floor 65, thecontinuous-extraction system 50 utilizes a haulage conveyor 60 that iselevated above the mine floor 65 and cantilevered from one of the walls62 of the roadway entry 6 (see FIG. 10). This configuration allows forsubstantially unrestricted access to all areas of the block-cavinginfrastructure 8 because the mine floor 65 remains unobstructed. Byhaving the mobile crusher 56 positioned within the roadway entry 6proximal to the draw-bell 4 from which the LHD 52 is extracting ore 2,the amount of time spent tramming by the LHD 52 is dramatically reducedcompared to known systems that utilize massive, centrally-locatedunderground dump points with large, immovable crusher assemblies.

Although various configurations are possible, the illustrated LHD 52includes a front end 64 with a moveable load bucket 66 operable tocollect, carry, and dump ore 2. The front end 64 is pivotally coupled toa rear end 68 of the LHD 52. The pivotal coupling allows the LHD 52 tobe articulated in two parts and helps negotiate curves. The rear end 68includes an operator cab 70 and an integrated drive mechanism and powersource 72. Like the loading machine 18, the LHD 52 can include a rockbreaker such as a jack hammer on the front end 64 to break down largelumps of ore 2 that would otherwise be too large for the bucket 66 tocollect. Although FIG. 8 illustrates a single moveable load bucket 66 onthe front end 64 of the LHD 52, other LHD 52 embodiments can include abucket 66 on both the front end 64 and the rear end 68, with theoperator cab 70 and the power source 72 interposed between the twobuckets 66. The LHD 52 may also be configured for remote operation,thereby eliminating the need for the operator cab 70.

The drive mechanism and power source 72 may be electrical orelectro-hydraulic, and may be powered by batteries or by an externalpower source. In some embodiments, each wheel of the LHD 52 may includeits own dedicated electronic drive that comprises, for example, anelectric motor and accompanying gearbox. In this way, each wheel can becontrolled independently by an associated variable frequency drivesystem or a chopper drive system, thus reducing or eliminating the needfor mechanical transfer cases and differentials. Where external power isused, the LHD 52 is provided with a suitable cable handling system.Because of the mobile crusher 56, the LHD 52 is only required to tramthe relatively short distance between the draw-bells 4 and the mobilecrusher 56, which enables the use of batteries as a means of poweringthe LHD 52. In the illustrated construction, the power source 72 at therear end 68 of the LHD 52 is made up of a battery tray. Alternatively,the LHD 52 may be powered by a diesel engine. In some embodiments, theLHD 52 is driven or powered at least in part by a “drop-in”diesel-electric power pack or similar generator set that includes aninternal combustion engine coupled to a generator or other suitabledevice for producing electrical power from the work performed by theengine. Such a generator set may supplement an otherwise primarilyelectrical drive mechanism and power source and may be capable ofdriving and powering all operations of the continuous miner without theneed for external power.

With continuing reference to FIG. 9, feeder 54 includes a gather portion74 where it receives ore 2 from the LHD 52, and a conveyor portion 76where it transports the ore 2 to the mobile crusher 56. The gatherportion 74 includes wings 78 that are attached to the left and rightsides of the feeder 54 and guide the ore 2 to the conveyor portion 76.In some embodiments, the wings 78 are pivotally attached to the gatherportion 74 and can fold up as the ore 2 is transported to the mobilecrusher 56. The foldable wings 78 can help guide and feed the ore 2 tothe conveyor portion 76. The conveyor portion 76 of the feeder 54 canemploy a plate-type conveyor, an armored-face conveyor, or otherconveyors that are known in the art. In some constructions, the feeder54 is driven by its own integrated drive system (not shown). Otherconstructions of the feeder 54 can be towed by mobile crusher 56.Although FIG. 9 illustrates a single feeder 54 transporting the ore 2 tothe mobile crusher 56, in other embodiments more than one feeder 54 cantransport the ore 2 to the mobile crusher 56, for example from opposingsides of the mobile crusher 56.

With continuing reference to FIGS. 9 and 10, mobile crusher 56 or sizeris operable to crush or size the material and deposit the material ontothe bridge conveyor 58. The crusher 56 includes a crusher portion 80that is mounted on drive treads 82. One or more cylindrical rollers 83with associated bits are mounted in the crusher portion 80 and crush orsize the ore 2. The crusher 56 is moveable along the mine floor 65 andcan be positioned anywhere along the length of the haulage conveyor 60.Although FIG. 9 illustrates the mobile crusher 56 with drive treads 82,other embodiments can include track-type crawlers, rubber-tired wheels,or substantially any other type of support that allows for movement ofthe crusher 56. In some embodiments, movement of the mobile crusher 56is controlled by an automated system using inertial or other types ofnavigation or guidance, such that the mobile crusher 56 is automaticallyadvanced along roadway entry 6 in sequence with movement of the LHD 52.The mobile crusher 56 is operatively driven by a primary drive and powercenter that may be or include electrical, electro hydraulic, or acombination of electric and hydraulic motors, and in some embodimentsmay be powered at least in part by diesel power. As discussed above,depending on the mining environment in which the system 50 is deployed,material extracted from the draw-bells 4 may be such that a crusher orsizer is not required. In such cases, the crusher portion 80 can bereplaced by a somewhat simplified material collector that may includeintermediate conveyors, funnels and/or chutes for collecting materialreceived from the LHD 52 and transferring it to the bridge conveyor 58.

With continuing reference to FIGS. 9 and 10, bridge conveyor 58 extendsgenerally upwardly toward the roof 63 of the roadway entry 6 from alocation proximal to the floor 65. The bridge conveyor 58 upwardlyconveys material received from the mobile crusher 56 and deposits thematerial onto the haulage conveyor 60. The bridge conveyor 58 cancontain portions with different slopes. Some embodiments of the bridgeconveyor 58 may also include support legs. The bridge conveyor 58 may beseparate from or integral with the mobile crusher 56, and may be drivenor powered by its own independent drive system or by the drive system ofthe crusher 56. The bridge conveyor 58 is therefore moveable along themine floor 65 and can be positioned anywhere along the length of thehaulage conveyor 60. In the illustrated construction, the bridgeconveyor 58 is based on an endless belt-type conveyor; however, otherconveyor types may also be used. In some constructions, the bridgeconveyor 58 is pivotable with respect to the mobile crusher 56 or isotherwise adjustable to the right or left to accommodate different mineconfigurations.

With continuing reference to FIGS. 9 and 10, the elevated andcantilevered haulage conveyor 60 is positioned proximal to the roof 63and coupled to one of the sidewalls 62 of the roadway entry 6 in acantilevered manner. In some embodiments, the haulage conveyor 60 issupported solely by the wall 62. In further embodiments, the haulageconveyor 60 is positioned at least half way up the wall 62 between theroof 63 and the floor 65. In other embodiments, the haulage conveyor 60is positioned at least two-thirds of the way up the wall 62 between theroof 63 and the floor 65. In further embodiments, the roadway entry 6includes a centerline, and the entire haulage conveyor 60 is positionedto one side of the centerline. Stated slightly differently, the haulageconveyor 60 is off-center when viewed in the longitudinal direction ofthe roadway entry 6.

The illustrated haulage conveyor 60 is a trough conveyor and includes aset of trough rollers 84 that support the conveying run of the conveyorbelt 61, and a set of lower rollers 86 that support the return run ofthe conveyor belt 61. The haulage conveyor 60 is supported by aplurality of L-brackets 88. Each L-bracket 88 has a substantiallyvertical leg that is coupled to the mine wall 62, and a substantiallyhorizontal leg that extends beneath and supports the haulage conveyor60. Because the haulage conveyor 60 is elevated from the mine floor 65,the presence of undulations or other deformation of the mine floor 65does not hinder performance of the conveyor 60. The elevated andcantilevered haulage conveyor 60 receives crushed ore from the bridgeconveyor 58 and conveys the crushed ore to the transverse transportentry 11 (see FIG. 2) and out of the mine.

Referring to FIG. 11, in operation, the LHD 52 moves into the draw-bell4 via the draw-bell entry 9 to collect ore 2 with the moveable loadbucket 66. To this end, the bucket 66 is first crowded into thedraw-bell 4 and then pivotably swung about a transverse axis. As thebucket 66 is loaded, the LHD 52 trams backwards until the LHD 52 is onceagain positioned on the roadway entry 6. The LHD 52 then advances to thefeeder 54, which is positioned in the roadway entry 6 beyond thedraw-bell entry 9, and the LHD 52 dumps the ore 2 from the load bucket66 into the gather portion 74 of the feeder 54. The feeder 54 moves theore 2 from the gather portion 74 to the conveyor portion 76, and theconveyor portion 76 drops the ore into the crusher 56. The crusher 56crushes or sizes the ore 2 (if necessary), and deposits the ore onto thebridge conveyor 58. The bridge conveyor 58 transports the crushed oreupwardly and away from the crusher 56 to the elevated haulage conveyor60. The haulage conveyor 60 then transports the crushed ore to thetransverse transport entry 11 (see FIG. 2), where it is subsequentlycarried away and out of the mine. After dumping the ore 2 in the feeder54, the LHD 52 trams backwardly along the roadway entry 6 beyond thedraw-bell entry 9, and then trams forwardly and turns into the draw-bellentry 9 to return to the draw-bell 4 for removal of additional material.The LHD 52 then repeats the ore-loading process. When the LHD 52finishes collecting material from one draw-bell 4, thecontinuous-extraction system 50 moves along the roadway 6 to the nextdraw-bell entry 9. Specifically, the feeder 54, the mobile crusher 56,and the bridge conveyor 58 of the continuous-extraction system 50 trambeyond the next draw-bell entry 9, and thereby provide the LHD 52 withaccess to the next draw-bell 4. In a block-cave infrastructure 8 withmultiple draw-bells 4, a plurality of continuous-extraction systems 50can be employed to improve production rates.

FIG. 12 illustrates a modified version of the continuous-extractionsystem 50 shown in FIG. 11 whereby the LHD 52 is replaced with a loaderin the form of a loading machine 118 similar to the loading machine 18illustrated in FIG. 7. The continuous-extraction system 150 of FIG. 12includes a crawler-mounted or wheel-mounted material collector 156,which may include a crusher portion 180, as illustrated. The system 150also includes a bridge conveyor 158 that carries material from thematerial collector 156 upwardly to an elevated and cantilevered haulageconveyor 160 that is cantilevered from the sidewall 62 of the roadwayentry 6. Although the illustrated construction does not include afeeder, a feeder similar to the feeder 54 discussed above may also beincluded in the continuous-extraction system 150.

The loading machine 118 includes a chassis 138 including a conveyor 126extending from a collection end 139 to a discharge end 140 of thechassis 138. The collection end 139 of the chassis 138 also includes acollection tray 127 optionally including a pair of rotating collectorwheels (not shown) that guide material onto the conveyor 126. Theloading machine 118 also includes a carriage assembly 131 that ismoveable in the fore and aft direction along the chassis 138 and hasmounted thereto a backhoe-type loading arm 130. The loading arm 130 isoperable to reach beyond the front end of the chassis into the draw-bell4 and to move (e.g., to pull) material onto the collection tray 127. Theloading arm 130 can also include a rock breaker (not shown but similarto the rock breaker 32 of FIGS. 3-8) operable to break down large lumpsof ore 2 that would be too large for the loading arm 130 to collect andmaneuver onto the collection tray 127. The loading machine 118 alsoincludes steerable treads or wheels 117 (wheels are shown in FIG. 12)for movement over the mine floor. The wheels 117 are rotatable about agenerally vertical axis for movement in a variety of directions, and arealso vertically moveable relative to the chassis 138 of the loadingmachine 118 for raising and lowering the chassis relative to the minefloor 65.

The discharge end 140 is pivotally coupled to the material collector 156and may include a funnel or other guide member 142 for guiding materialfrom the conveyor 126 into the crusher section 180. The pivotal couplingbetween the discharge end 140 and the material collector 156 allows theloading machine 118 to be pushed or pulled by the material collector 156for movement into and out of the draw-bell entries 9 and for movementalong the roadway entries 6. In operation, the wheels or treads of thematerial collector 156 are operated to move the material collector 156and the loading machine 118 in the fore and aft direction. The wheels117 of the loading machine 118 are then steered as needed to guide theloading machine into and out of the draw-bell entries 9. When thecollection end 139 of the loading machine 118 is positioned adjacent thedraw bell 4, the loading arm 130 pulls material onto the collecting tray127 and the material is then conveyed rearwardly by the conveyor 126 anddropped into the material collector 156. The material is then crushed(if necessary) by the crusher section 180 and transferred to the bridgeconveyor 158 and, finally, to the haulage conveyor 160, which transportsthe material to along the roadway entry 6 and eventually out of themine. The continuous-extraction system 150 is thus able to move alongthe roadway entry 6 under the motive power provided by the materialcollector 156 and position the loading machine 118 into a draw-bellentry 9. After the loading machine 118 has finished gathering materialfrom the draw-bell 4, the material collector 156 and the steerablewheels 117 are operated in a coordinated manner to remove the loadingmachine 118 from the draw-bell entry 9, tram further along the roadwayentry 6 to the next draw-bell entry 9, position the loading machine 118into the next draw-bell entry 9, and repeat the process.

What is claimed is:
 1. A load haul dump vehicle for moving materialthrough an underground mine, the vehicle comprising: a front endincluding a moveable load bucket; a rear end pivotally coupled to thefront end; and an electrical drive operable to move the load bucket andthe vehicle.
 2. The vehicle of claim 1, wherein the front end includes apair of front wheels and the rear end includes a pair of rear wheels,and wherein the electrical drive is operable to rotate the front wheelsand the rear wheels.
 3. The vehicle of claim 2, wherein each of thefront wheels and each of the rear wheels includes a dedicated electricdrive assembly for independently rotating an associated front wheel orrear wheel.
 4. The vehicle of claim 1, wherein the electrical drive isoperable to pivot the front end and the rear end relative to oneanother.
 5. The vehicle of claim 1, wherein the electrical driveincludes a battery assembly.
 6. The vehicle of claim 1, wherein theelectrical drive includes a cable management system for coupling with anexternal power supply that is fixed relative to the mine.
 7. The vehicleof claim 1, wherein the front end includes a rock breaker positionedadjacent the load bucket.
 8. The vehicle of claim 1, wherein the rearend includes a second moveable load bucket.
 9. The vehicle of claim 1,wherein the electrical drive is operable to power a hydraulic system,and wherein the hydraulic system is operable to pivot the front end andthe rear end relative to one another.
 10. The vehicle of claim 1,further comprising an internal combustion engine for supplementing theelectrical drive.